Gas pipelines require large compressors to force gas through the pipelines. These compressors may have a fan width of more than 12 feet, and move more than 200,000 cubic feet of air per minute. These compressors and their cooling fans generate significant noise, such that they may create a nuisance for those nearby. For this reason, attempts have been made to make the compressors as quiet as possible, such as by modifying the shapes of the cooling fan blades. However, there are many compressors in existence that are not quiet and that continue to create a nuisance. While the compressors are usually located in isolated areas, continued expansion of residences and decreasing tolerance for environmental noise have created a conflict between existing compressors and people living near them.
It has therefore become desirable to reduce the noise emitted by compressors, and particularly their cooling fans, and it is therefore an object of the present invention to reduce the noise emitted by large compressors.
Noise reduction in large compressors is not an easy task particularly when it is desired to reduce the noise emitted by the air intake of the cooling fan of a compressor. The reason for this is that conventional silencers (as for example used on motor vehicles) create a considerable pressure drop that is unacceptable across the air intake of the cooling fan. With a large pressure drop, air supply is reduced which may result in over heating of the gas being conveyed in the pipeline or of the compressor itself, especially on a hot day (&gt;90.degree. F.). It is therefore a further object of this invention to provide a noise reduction unit for a cooling fan of a compressor unit that allows relatively free flow of air into the cooling fan of the compressor unit.
One design for an acoustic chamber is shown in U.S. Pat. No. 5,332,872 by the same inventor. While this design has had some success, tighter environmental regulations require improved noise control. It is therefore an object of this invention to provide improved noise control for air intakes of gas compressors.